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path: root/src/pkg/crypto/cipher/ocfb.go
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Diffstat (limited to 'src/pkg/crypto/cipher/ocfb.go')
-rw-r--r--src/pkg/crypto/cipher/ocfb.go138
1 files changed, 0 insertions, 138 deletions
diff --git a/src/pkg/crypto/cipher/ocfb.go b/src/pkg/crypto/cipher/ocfb.go
deleted file mode 100644
index 031e74a9d..000000000
--- a/src/pkg/crypto/cipher/ocfb.go
+++ /dev/null
@@ -1,138 +0,0 @@
-// Copyright 2010 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// OpenPGP CFB Mode. http://tools.ietf.org/html/rfc4880#section-13.9
-
-package cipher
-
-type ocfbEncrypter struct {
- b Block
- fre []byte
- outUsed int
-}
-
-// An OCFBResyncOption determines if the "resynchronization step" of OCFB is
-// performed.
-type OCFBResyncOption bool
-
-const (
- OCFBResync OCFBResyncOption = true
- OCFBNoResync OCFBResyncOption = false
-)
-
-// NewOCFBEncrypter returns a Stream which encrypts data with OpenPGP's cipher
-// feedback mode using the given Block, and an initial amount of ciphertext.
-// randData must be random bytes and be the same length as the Block's block
-// size. Resync determines if the "resynchronization step" from RFC 4880, 13.9
-// step 7 is performed. Different parts of OpenPGP vary on this point.
-func NewOCFBEncrypter(block Block, randData []byte, resync OCFBResyncOption) (Stream, []byte) {
- blockSize := block.BlockSize()
- if len(randData) != blockSize {
- return nil, nil
- }
-
- x := &ocfbEncrypter{
- b: block,
- fre: make([]byte, blockSize),
- outUsed: 0,
- }
- prefix := make([]byte, blockSize+2)
-
- block.Encrypt(x.fre, x.fre)
- for i := 0; i < blockSize; i++ {
- prefix[i] = randData[i] ^ x.fre[i]
- }
-
- block.Encrypt(x.fre, prefix[:blockSize])
- prefix[blockSize] = x.fre[0] ^ randData[blockSize-2]
- prefix[blockSize+1] = x.fre[1] ^ randData[blockSize-1]
-
- if resync {
- block.Encrypt(x.fre, prefix[2:])
- } else {
- x.fre[0] = prefix[blockSize]
- x.fre[1] = prefix[blockSize+1]
- x.outUsed = 2
- }
- return x, prefix
-}
-
-func (x *ocfbEncrypter) XORKeyStream(dst, src []byte) {
- for i := 0; i < len(src); i++ {
- if x.outUsed == len(x.fre) {
- x.b.Encrypt(x.fre, x.fre)
- x.outUsed = 0
- }
-
- x.fre[x.outUsed] ^= src[i]
- dst[i] = x.fre[x.outUsed]
- x.outUsed++
- }
-}
-
-type ocfbDecrypter struct {
- b Block
- fre []byte
- outUsed int
-}
-
-// NewOCFBDecrypter returns a Stream which decrypts data with OpenPGP's cipher
-// feedback mode using the given Block. Prefix must be the first blockSize + 2
-// bytes of the ciphertext, where blockSize is the Block's block size. If an
-// incorrect key is detected then nil is returned. On successful exit,
-// blockSize+2 bytes of decrypted data are written into prefix. Resync
-// determines if the "resynchronization step" from RFC 4880, 13.9 step 7 is
-// performed. Different parts of OpenPGP vary on this point.
-func NewOCFBDecrypter(block Block, prefix []byte, resync OCFBResyncOption) Stream {
- blockSize := block.BlockSize()
- if len(prefix) != blockSize+2 {
- return nil
- }
-
- x := &ocfbDecrypter{
- b: block,
- fre: make([]byte, blockSize),
- outUsed: 0,
- }
- prefixCopy := make([]byte, len(prefix))
- copy(prefixCopy, prefix)
-
- block.Encrypt(x.fre, x.fre)
- for i := 0; i < blockSize; i++ {
- prefixCopy[i] ^= x.fre[i]
- }
-
- block.Encrypt(x.fre, prefix[:blockSize])
- prefixCopy[blockSize] ^= x.fre[0]
- prefixCopy[blockSize+1] ^= x.fre[1]
-
- if prefixCopy[blockSize-2] != prefixCopy[blockSize] ||
- prefixCopy[blockSize-1] != prefixCopy[blockSize+1] {
- return nil
- }
-
- if resync {
- block.Encrypt(x.fre, prefix[2:])
- } else {
- x.fre[0] = prefix[blockSize]
- x.fre[1] = prefix[blockSize+1]
- x.outUsed = 2
- }
- copy(prefix, prefixCopy)
- return x
-}
-
-func (x *ocfbDecrypter) XORKeyStream(dst, src []byte) {
- for i := 0; i < len(src); i++ {
- if x.outUsed == len(x.fre) {
- x.b.Encrypt(x.fre, x.fre)
- x.outUsed = 0
- }
-
- c := src[i]
- dst[i] = x.fre[x.outUsed] ^ src[i]
- x.fre[x.outUsed] = c
- x.outUsed++
- }
-}